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DNS, NameServers being sub domain of whats they are NS's for

Posted on 2004-11-11
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Last Modified: 2010-04-10
I have the domain coolnicks.co.uk. and a large number of other domains.

On coolnicks.co.uk two of the sub domains are ns0.coolnicks.co.uk and ns1.coolnicks.co.uk pointing to different DNS servers i host. all the other domains use these two sub domains of coolnicks as their DNS servers and some are very important meaning they cannot experience any down time.

At the moment the name servers for coolnicks.co.uk are done with a dynamic DNS service, what I would like to do is avoid this as it causes a number of extra lookups.

So what I would like to do is set the DNS servers of coolnicks.co.uk to ns0.coolnicks.co.uk and ns1.coolnicks.co.uk.

As I understand this will work ok as the root servers will provide glue and pass along the IPs as well (otherwise there will be an infinitive loop wont there?), the problem is how do the root servers get these IP's? Are they updated into the whois info...e.g. the registrar sends both the dns names and IPs to be stored, or do the root servers look up the IPs their selves. If so do they do then cache it or resolve it each time the name servers?

There is a possibility one of the IPs will change from time to time, so will i have to update the whois name server info or will the root servers auto do this?

I hope that is understand-able and somebody can answer it :)

Nick
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Question by:coolnicks
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kain21 earned 300 total points
ID: 12555377
when you change the nameservers to the ns0.coolnicks.co.uk the whois database will be updated with the corresponding ip address... it will cache the ip address and check for updates when the cache expires... that's the reason for needing atleast two dns server... if one changes ips then clients can use the other dns server until the cache at the root server updates itself...
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by:Chris Dent
Chris Dent earned 75 total points
ID: 12555497

Just some little things.

The addresses you quoted at the top are hosts rather than subdomains. ns1.coolnicks.co.uk is a host, ns1.subdomain.coolnicks.co.uk is a host in a subdomain.

The majority of Root Name Servers run non-caching DNS, I can't remember which specific DNS software that is, but I'm sure I can find it again if you're interested.

The IP Addresses for your Name Servers are registered with your Naming Authority, these are added to one of the Root Name Servers.

Since the Root Servers aren't Start of Authority for your specific domain (and because they don't cache) they will be unable to answer further questions about your domain, so those are passed directly along to your own Name Servers, which of course are Start of Authority for the domain.

If your Name Server addresses change you will need to handle a manual change with your domain registrar - depending on which one you use of course.
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by:coolnicks
ID: 12556386
>>The IP Addresses for your Name Servers are registered with your Naming Authority, these are added to one of the Root Name Servers.

So the root dns servers store the ip and dns?

>>If your Name Server addresses change you will need to handle a manual change with your domain registrar - depending on which one you use of course.

So the IPs stored in the root dns wont change if the ip of the dns changes and i have to manualy update them?

Cheers

Nick

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by:kain21
kain21 earned 300 total points
ID: 12556429
> So the IPs stored in the root dns wont change if the ip of the dns changes and i have to manualy update them?

you would not need to change the ip address with your naming authority... it would automatically update after you change the host record for your dns server...
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by:Chris Dent
ID: 12556464

The Root Servers store really basic information, only the Name Server addresses or a place you can find the name server addresses. They don't store anything else (like www etc) your server is required to answer questions about those addresses.

Yes you have to manually update them - although that method varies depending on which Naming Authority you use and you're best asking whatever registrar you used to buy the domain.
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by:kain21
kain21 earned 300 total points
ID: 12556512
I don't agree with Chris-Dent... we currently use ns1.mydomain.com, ns2.mydomain.com, and ns3.mydomain.com... with our naming authority... which is network solutions... we have ns1.mydomain.com, ns2.mydomain.com, and ns3.mydomain.com listed as the nameservers for mydomain.com... when we need to change the ip address of one of our nameservers all we have to do is login to our dns server and update the host record for the nameserver... it then automatically updates with network solutions since the actually hostname did not change...
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Author Comment

by:coolnicks
ID: 12556812
kain21.....that is the answer im looking for :)

so does the root dns server cache the IP of the ns record or look it up each time from my dns server?

would it take the normal 24-48 hours to propagate the new ip for the ns record?

Some registrars ask for the dns and ip of both nameservers (the rest look it up??), why is this if they only need the dns of the ns's?

Although....ive just thought.... in a normal dns file under the ns section it stores both the dns and ip :s

Nick
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by:Chris Dent
ID: 12557588

Kain21 is right, I just need to figure out how the registrar gets the IP addresses for your name servers. Sorry for the misleading (or wrong) information.

:)

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by:kain21
ID: 12557911
Nick,

I'm testing the IP change now... network solutions caches the record... if you adjust your TTL value to an hour or two it will increase the number DNS request to your server but IP changes like the one you are talking about will propagate quicker...
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by:Chris Dent
ID: 12558200

Name Server Records have a (default) cache time of 2 days.

Really any change to the TTL at least that far (2 days) in advance so the cached records elsewhere else in the world have had a chance to expire.

You can see the TTL on a record from NSLookup by using "set debug".
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Author Comment

by:coolnicks
ID: 12561208
kain21 ... did you get the results of testing the IP change? just looking in my DNS server and it looks like the TTL is 2day atm.

From what you have both said i think i may try and change it over tommorow to see what happends.

Keep the comments coming tho is there is anything else :)

Nick
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by:kain21
ID: 12565215
Yeah.. my TTL was 24 hours... it updated accordingly...
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Author Comment

by:coolnicks
ID: 12989740
Thanks all

Running nice and smoothly now
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